The concepts and embodiments disclosed herein relate to the technical field of measurement data acquisition. Typically, measurement data are obtained by using a sensor unit. The sensor unit comprises a transducer coupled to the probe that is sensitive to a physical quantity to be detected. The transducer is configured to output an analog measurement signal (herein also referred to as analog sensor signal) that is commensurate with an amount of the physical quantity as ‘seen’ by the probe.
In many applications it is impossible to place processing device in the immediate vicinity of the transducer. Consequently, the analog measurement signal needs to travel a certain distance before being processed. The longer the distance that the analog measurement signal needs to travel, for example on a transmission line, the more the analog measurement signal distorted or otherwise deteriorated, for example due to damping or due to noise on the transmission line, and the less the analog measurement signal eventually seen may still be a true representation of the measured quantity. Therefore, the sensor unit may comprise an analog to digital converter that is located in proximity to the transducer and coupled to the transducer in order to receive the analog sensor signal and configured to output a digital sense signal that represents essentially the information acquired by a transducer. In a typical application the sensor unit is coupled to the processing unit and configured to transmit the digital sense signal to the processing unit for processing. Since the transmission of digital signals is typically more robust against adverse effects of damping and noise, the digital sense signal received at the processing unit provides a representation of the measured quantity that is closer to the truth than a direct transmission of the analog signal from the transducer to the processing unit could provide.
Sometimes measurement of a given physical quantity requires the corresponding sensor unit to operate in harsh electrical conditions. In particular, a reference voltage, for example provided by ground, many vary wildly. Therefore, a barrier can be provided that electrically separates the sensor unit from the control unit. At the barrier, a sensor reference voltage, herein also referred to as sensor ground potential, used in the measurement data acquisition, and a controller reference voltage, herein also referred to as control unit ground potential, used in the processing of acquired data, are separated from one another.
Interfaces to communicate across barriers that effectively separate electrical conditions on the side of the control unit from the harsh electrical conditions on the side of the sensor unit require significant effort in engineering and quality.